Protective Effects of Curcumin on the Outcome of Cryopreservation in Human Sperm

The application of mean number of DNA breakpoints in sperm cryopreservation

Growing concerns over declining male semen quality and rising infertility have shifted attention to male fertility. Sperm cryopreservation emerges as a crucial tool in preserving male fertility, especially for patients who need proactive preservation, such as cancer patients before undergoing radiation or chemotherapy. Although cryopreservation does not directly address infertility, effective preservation can support future fertility. However, the process may compromise sperm DNA integrity. Despite their impairment, damaged sperm often retain vitality and may still have the potential to fertilize an egg. Nonetheless, if damaged sperm fertilize an egg, excessive DNA damage could impede embryo implantation and development, despite the egg's repair capabilities. Consequently, precise detection of sperm DNA damage is crucial and urgent. To better address the issue of sperm DNA damage detection, we have introduced a novel fluorescence biosensor technology known as the TDT/SD Probe. This technology utilizes terminal deoxynucleotidyl transferase (TdT) and strand displacement probes to accurately detect the number of sperm DNA breakage points during the cryopreservation process. Experimental results reveal that the number of sperm DNA breakpoints significantly increases after both sperm vitrification (8.17 × 105) and conventional slow freezing (10.80 × 105), compared to the DNA breakpoints of fresh semen samples (5.19 × 105). However, sperm vitrification has the least impact on sperm breakage points. This research provides innovative means for further optimizing sperm preservation techniques by offering a novel DNA damage detection method, enabling more precise assessment of sperm DNA damage during the freezing process.

Effect of Conditioned Medium from Human Adipose-Derived Mesenchymal Stem Cells on Human Sperm Quality During Cryopreservation

The cryopreservation procedure decreases sperm quality, causing certain changes at structural and molecular levels affecting fertilizing ability. We aimed to investigate the impacts of human adipose-derived mesenchymal stem cells (HAd-MSCs) conditioned medium (CM) on the protection of human sperm from cryoinjury. Thirty normal semen specimens were evaluated in this study. Each specimen was separated into six groups and enhanced with varying concentrations of human Ad-MSCs-CM (0, 10, 30, 50, 70, and 100%). Sperm motility, viability, morphology, apoptosis, mitochondrial potential, and lipid peroxidation, and DNA fragmentation were evaluated before freezing and after thawing. The results showed that the total motility was preserved in 10% human Ad-MSCs-CM group. Also, DNA fragmentation was significantly lower in 10% compared to 0% human Ad-MSCs-CM (63.62 ± 17.72% vs.76.46 ± 4.87%, respectively, P < 0.004). Human Ad-MSCs-CM in groups of 10, 30, 50, and 70% reduced lipid peroxidation. The normal sperm morphology rate, mitochondrial membrane potential, and apoptosis showed no significant differences across various groups. It seems that human Ad-MSCs-CM can protect the sperm parameters during the cryopreservation by decreasing cryoinjury.

A Key regulatory protein QRICH2 governing sperm function with profound antioxidant properties, enhancing sperm viability

Infertility poses a global health and social challenge, affecting approximately 15% of couples at childbearing age, with half of the cases attributed to male factors, wherein genetic factors exert a substantial role. In our prior investigation, we identified loss-of-function variants within the gene encoding glutamine-rich protein 2 (QRICH2) in two consanguineous families, leading to various morphological abnormalities in sperm flagella and male infertility. Moreover, our observations in Qrich2 knockout mice revealed a pronounced reduction in spermatozoa count. However, the underlying mechanism remains elusive, prompting further investigation in the current study. By conducting experiments such as Hematoxylin-eosin (HE) staining, immunofluorescence staining, flow cytometry, and single sperm metabolism analysis on the testes and spermatozoa of Qrich2 knockout mice, we found a strong antioxidant capacity mediated by QRICH2 both in vivo and in vitro. Qrich2 knockout led to elevated levels of ROS, consequently inducing DNA damage in spermatids, which in turn triggered increased autophagy and apoptosis, ultimately causing a significant decrease in spermatozoa count. Incubation with the N-terminal purified protein of QRICH2 exhibited potent strong antioxidant activity at the cell and spermatozoa levels in vitro, thereby enhancing spermatozoa viability and motility. Therefore, QRICH2 plays a crucial role in safeguarding spermatids from excessive ROS-induced damage by augmenting antioxidant capacity, thereby promoting spermatozoa survival and improving motility. Furthermore, the N-terminal purified protein of QRICH2 shows promise as an additive for protecting spermatozoa during preservation and cryopreservation.

Effect of crocin and quercetin supplementation in cryopreservation medium on post-thaw human sperm quality

Biochemical and physical changes during the cryopreservation process adversely affect sperm function required for fertilization. Recently, many studies have been conducted to find effective pre-freezing treatments to limit these damages. The present study aimed to investigate the effects of pre-freezing treatment with quercetin and crocin, individually or in combination, on sperm parameters after thawing procedure. For this, semen samples from 20 normozoospermic men were collected and then each sample was divided into five equal parts: 1. fresh group 2. frozen-thawed group without addition of antioxidants 3. frozen-thawed group containing 1 mM crocin, 4. frozen-thawed group containing 50 μM quercetin, and 5. frozen-thawed group containing a combination of 1 mM crocin and 50 μM quercetin. Pre-cryopreservation and post-thaw sperm motility, morphology, viability, DNA fragmentation, reactive oxygen species [1] (ROS) levels, and mitochondrial membrane potential [2] (MMP) were investigated. Cryopreservation significantly reduced sperm quality. Both crocin and quercetin individually improved sperm progressive motility, decreased ROS levels, reduced DNA fragmentation, and marginally increased MMP, though crocin seems to be more successful in protecting sperm quality. More interestingly, the combined addition of crocin and quercetin to the sperm-freezing medium did not show positive effects on sperm quality. Crocin and quercetin may play a role in mitigating the cryopreservation-induced injury to sperm.

The ameliorative effects of curcumin nanomicelle on testicular damage in the mouse model of multiple sclerosis

BACKGROUND

This study investigated the effect of curcumin nanomicelle (CUR-n) on the structure of testis tissue, the process of spermatogenesis, LH, FSH, testosterone, and oxidative stress in a model of multiple sclerosis.

METHODS

Twenty-four male mice C57BL/6 were randomly allocated into 4 groups of 6 (1: group receiving 2% CPZ diet, 2: group receiving the diet of 2% CPZ + CUR-n with a dose of 50 mg/kg, 3: group receiving the diet of 2% CPZ + CUR-n with a dose of 100 mg/kg). The concentration of hormones (testosterone, LH and FSH), was measured by the special hormone assay ELISA kits. Measuring total antioxidant capacity (TAC) and Malondialdehyde (MDA) levels was done by spectrophotometry and calorimetric methods, respectively. Stereological analysis was done in order to explore the number of spermatogenesis cells, testis and sperm properties.

RESULTS

The results indicated that CUR-n (100 mg/kg) significantly enhanced the concentration of LH, FSH, testosterone, and TAC but reduced MDA levels. It also notably increased the quantity of spermatogonia, spermatocyte, round spermatids, long spermatids and LCs, augmented testis weight and volume, and germinal epithelium volume, improved sperm count, morphology, viability, and motility. In addition, a considerable decrease in the amount of wrinkling and disruption of the germinal epithelium was observed after intervention with CUR-n (100 mg/kg). Furthermore, a significant increase in the number of germ cells compared to the group receiving CPZ was detected.

CONCLUSION

This study proposes that CUR-n could be a therapeutic agent for decreasing the adverse effects of MS on testis.

Preparation, characterization, and ex-vivo evaluation of curcumin-loaded niosomal nanoparticles on the equine sperm quality during cooled storage

Oxidative damage to sperm during cooled storage is a significant issue, and curcumin, with its antioxidant properties, could be a solution. However, its low bioavailability presents a challenge that this study aims to address. The primary objective of this study was to investigate the potential of curcumin-loaded niosomal nanoparticles (Cur-LNN) to enhance the antioxidant properties of curcumin and its effect on sperm quality during 72 h cooled storage. The thin-film hydration procedure was applied to prepare Cur-LNN. The fabricated noisomal nanocarriers were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and Fourier-transform infrared (FT-IR) spectroscopy. Moreover, the encapsulation and loading efficiency, in vitro release study, and ex-vivo antioxidant functionality of Cur-LNN on the stallion sperm preserved under cooled storage conditions were assessed. The fabricated Cur-LNN was spherical in shape and had an average particle size of 163.1 ± 1.8 nm, a zeta potential of -34.1 ± 1.9 mV, a poly-dispersity index of 0.339 ± 0.045, an encapsulation efficiency of 92.34 ± 0.18 %, and a loading efficiency of 35.57 ± 1.36 %. Ex-vivo evaluation revealed that supplementation of the semen extender with Cur-LNN has the potential to enhance sperm quality by improving total and progressive motility, plasma membrane functionality, and lipid peroxidation. These results demonstrate that Cur-LNN exhibited stronger antioxidant and protective effects than curcumin. Although further in vivo investigations are warranted, our ex-vivo results suggest that Cur-LNN has the potential to attenuate oxidative damage and can be used to fortify the antioxidant capacity of equine semen under cooled storage conditions.

L-Proline: A Promising Tool for Boosting Cryotolerance and Fertilizing Ability of Cryopreserved Sperm in Animals

Sperm cryopreservation technology significantly contributes to the safeguarding of genetic resources, particularly for endangered species, and supports the use of artificial insemination in domestic animals. Therefore, cryopreservation can negatively affect sperm health and function leading to reduce the freezing ability and fertility potential. Therefore, it is essential to prioritize the improvement of cryotolerance in cryopreserved sperm to enhance reproductive efficiency and ensure sustainability in livestock herds. The main reason for sperm dysfunction after thawing may be related to the excessive amount of oxidative stress (OS) produced during cryopreservation. Scientists have different ways for counteracting this OS including the use of plant extracts, enzymes, minerals, anti-freezing proteins, and amino acids. Recently, one such amino acid is L-proline (LP), which has multiple roles such as osmotic and OS defense, nitrogen, and carbon metabolism, as well as cell survival and signaling. LP has been found in seminal plasma and has recently been added to the freezing extender to improve the various post-thaw parameters of sperm. This improvement is related to the ability of LP to reduce the OS, sustain the plasma membrane and to act as an osmoregulatory agent. Moreover, LP can suppress cell apoptosis by modulating intracellular redox in sperm. This review addresses the ongoing research on the addition of L-proline as an osmoregulatory agent in freezing extenders to increase the cryotolerance of animal spermatozoa to freeze-thaw.

Addition of Vitamin C Mitigates the Loss of Antioxidant Capacity, Vitality and DNA Integrity in Cryopreserved Human Semen Samples

Cryopreservation of human spermatozoa is a necessity for males suffering from infertility who cannot produce fresh semen for insemination. However, current ART cryopreservation protocols are associated with losses of sperm motility, vitality and DNA integrity, which are thought to be linked to the induction of oxidative damage and the toxic properties of commercial cryoprotectants (CPAs). Preventing or mitigating these losses would be hugely beneficial to sperm survival during ART. Therefore, in this in vitro investigation, lipid peroxidation, production of reactive oxygen species, movement characteristics, antioxidant capacity, vitality, and DNA integrity were examined in semen samples both pre- and post-cryopreservation with CPA supplementation. The findings revealed a 50% reduction in antioxidant capacity with CPA addition, which was accompanied by significant increases in generation of reactive oxygen species and formation of lipid aldehydes. These changes were, in turn, correlated with reductions in sperm viability, motility and DNA integrity. Antioxidant supplementation generated bell-shaped dose-response curves with both resveratrol and vitamin C, emphasising the vulnerability of these cells to both oxidative and reductive stress. At the optimal dose, vitamin C was able to significantly enhance vitality and reduce DNA damage recorded in cryopreserved human spermatozoa. An improvement in sperm motility did not reach statistical significance, possibly because additional pathophysiological mechanisms limit the potential effectiveness of antioxidants in rescuing this aspect of sperm function. The vulnerability of human spermatozoa to reductive stress and the complex nature of sperm cryoinjury will present major challenges in creating the next generation of cryoprotective media.

Evaluation of the effect of mitoquinone on functional parameters, DNA structure, and genes expression related to the apoptotic and antioxidants of human sperm after freezing-thawing

OBJECTIVE

Sperm freezing is considered as an effective way in assisted reproductive technology (ART) programs, it has detrimental effects on sperm function, due to the production of reactive oxygen species (ROS). This study aimed to investigate the potential of Mitoquinone (MitoQ) in inhibiting the production of mitochondrial ROS during sperm freezing.

METHODS

A total of 20 human normozoosperm samples were collected for this study. The samples were divided into four groups, each containing different concentrations of MitoQ (0, 0.2, 2, and 20 nM), and then subjected to the freezing process. After thawing, the sperm suspensions were evaluated for parameters including motility, morphology, acrosome integrity, adenosine triphosphate (ATP) level, intracellular ROS, viability, chromatin packaging, DNA denaturation, DNA fragmentation, as well as the expression of antioxidants (GPX, SOD) and apoptotic (Bax, Bcl2) genes.

RESULTS

The results showed that total and progressive mobility of sperms significantly increased in the 2 nM group, while significantly decreased in the 20 nM group (p ≤ 0.05). Sperm morphology did not significantly improve across all the tested concentrations (p ≥ 0.05). Intracellular ROS levels showed a significant decrease and increase in the concentrations of 2 and 20 nM, respectively (p ≤ 0.05). Furthermore, a significant increase was observed in viability, ATP, acrosome integrity, chromatin packaging, and non-denatured and non-fragmented DNA after treatment with 2 nM of MitoQ, compared with the control group (p ≤ 0.05). Regarding gene expressions, the relative expressions of oxidative stress genes were increased in the 2 nM group and decreased in the 20 nM group (p ≤ 0.05), while no significant difference was observed in the expressions of apoptotic genes compared with the control group (p ≥ 0.05). All the comparisons were made with respect to the control group.

CONCLUSION

Adding the optimal concentration of MitoQ (2 nM) to the sperm freezing medium not only improves sperm functional parameters and reduces DNA damages, but also stimulates the expression of antioxidant genes, leading to even greater benefits for sperm cryopreservation.

Progress on the roles of zinc in sperm cryopreservation

One of the effective methods for the long-term preservation of mammalian genetic resources is the cryopreservation of semen. However, a number of parameters, including diluents, the rate of freezing and thawing, cryoprotectants, etc., can easily alter the survival of frozen-thawed sperm. Numerous studies have documented the addition of a variety of zinc compounds, to the diluents used to cryopreserve sperm. The primary objective of this review is to briefly describe that adding zinc to diluents as an antioxidant significantly enhances frozen-thawed sperm quality. Second, a summary of the present understanding of zinc's molecular mechanism on semen cryopreservation is provided. Thirdly, this study addresses that nanoparticles of zinc can offer suggestions for raising cryopreservation effectiveness.

Effects of cryopreservation in the presence of Natural Deep Eutectic Solvents (NADESs) on sperm parameters

Natural Deep Eutectic Solvents (NADESs) are being considered as a potential alternative to traditional cryoprotective agents (CPAs) in sperm freezing. The study aimed to assess the effects of NADESs as a CPA on human sperm parameters. A total of 32 normozoospermic semen samples were collected from the Alzahra infertility treatment center (Iran) between July 2021 and September 2022. The samples were categorized into eight different groups: 1) a control (nonfrozen), and groups frozen with 2) SpermFreeze Solution, 3) ChX (Choline chloride and Xylitol), 4) ChS (Choline chloride and D-sorbitol), 5) ChG (Choline chloride and Glucose), 6) ChU (Choline chloride and Urea), 7) EtP (Ethylene glycol and l-proline), and 8) GlyP (Glycerol and l-proline). The study also analyzed the quality of sperm parameters, such as chromatin condensation and integrity, acrosome integrity, and survival, along with the expression of some genes that affect sperm fertility (TRPV1, TRPV4, SPACA3, and OGG1). The study found there were notable variations in sperm parameters (such as viability, chromatin condensation and integrity, and acrosome integrity) among frozen groups with some NADESs compared to the SpermFreeze Solution and control groups (P < 0.05). Analysis of gene expression demonstrated that the levels of TRPV1, TRPV4, SPACA3, and OGG1 genes were superior in the GlyP group compared to the other groups (P < 0.05). Additionally, the ChS and ChU groups exhibited preserved expression of these genes compared with the SpermFreeze Solution group. The use of NADESs led to the discovery of a more appropriate CPA that has low toxicity and is highly effective in maintaining the fertility potential of sperm.

The effects of coenzyme Q10 and curcumin supplementation in freezing medium for human sperm cryopreservation

BACKGROUND

Despite its routine and frequent application, cryopreservation of human sperm is far from the desired efficacy, as freezing and thawing impair motility, viability, acrosomal unity, and DNA integrity.

OBJECTIVES

In this study, the authors aimed to investigate whether adding antioxidants, coenzyme Q10, and curcumin into the freezing medium provide better efficacy in the cryopreservation of human sperm.

METHODS

The semen samples from 40 healthy men aged 18-45 were collected in sterile containers by masturbation. Samples within normal reference values for sperm concentration (≥15 million/mL) and motility (progressive motile ≥ 32% and total motility ≥ 40%) were included in the study. Semen samples were equally divided into five groups and evaluated; i) pre-freezing sperm suspension, ii) frozen-thawed control (Ctrl) without any supplementation in freezing medium, iii) frozen-thawed with curcumin supplementation of 0.25 mM (Cur), iv) frozen-thawed coenzyme Q10 supplementation of 25 µM (CoQ10) and v) frozen-thawed curcumin (0.25 mM) plus coenzyme Q10 (25 µM) supplementation (CurCoQ10) into the freezing medium. Liquid nitrogen vapour freezing and rapid thawing were performed in each group (ii-v). Sperm motility, viability, acrosome integrity, and DNA fragmentation rates were compared and ultrastructural evaluations by transmission electron microscopy were undertaken between the groups. Additionally, the total antioxidant capacity/total oxidant capacity values were measured.

RESULTS

According to CASA results, progressive motility was significantly higher in the CoQ10 group (9.4 ± 7.6) when compared with the Ctrl (7.1 ± 6.3), Cur (6.4 ± 4.8) and CurCoQ10 (8.1 ± 7.7) groups (p < 0.05). Flow cytometry results showed no difference in the viability and acrosome integrity values after thawing, but DNA fragmentation was significantly increased in the curcumin-added groups (p < 0.05). Acrosomal changes and sub-acrosomal defects were seen in all groups after thawing at the ultrastructural level. Mitochondrial membrane structure was preserved in CoQ10 and CurCoQ10 groups.

CONCLUSIONS

Our results suggested that sperm ultrastructural morphology and motility were better preserved in the CoQ10 group during cryopreservation. In curcumin groups, DNA fragmentation and head defects were increased.

Evaluation of Post-Thaw Swim-Up Selection Combined With Glutathione Addition for Improvement of Sperm Chromatin Maturity in Normozoospermic Samples

BACKGROUND

Cryopreservation of human semen alters the spermatozoal structure, resulting in a reduction in sperm function parameters. Various antioxidants may be able to slow or prevent this type of injury. Glutathione (GSH) has numerous antioxidant properties; supplementing the semen with GSH before freezing may assist in the restoration of post-thaw sperm functionality.

OBJECTIVE

 To investigate the effect of adding 5mM of glutathione before freezing on human sperm cryosurvival.

MATERIALS AND METHODS

Semen samples were collected from 30 patients (22 normozoospermic and 8 asthenozoospermic) after 3-5 days of sexual abstinence. Following liquefaction, macro- and microscopic examinations were performed. The samples were then divided into two equal aliquots: the first aliquot received 5 mM of glutathione before freezing, and the second aliquot was considered the control (without glutathione). The samples were frozen using the rapid cryopreservation method and then preserved for 7-10 days in a liquid nitrogen tank before being thawed. Thawed samples from each group were examined microscopically according to the WHO 2010 guidelines. Aniline blue was used to assess the maturity of the DNA. Then, the direct-swim-up technique was applied to thawed samples from both groups to select the best sperm quality.

RESULTS

The cryopreservation process negatively impacts all sperm characteristics in both groups. Sperm DNA integrity decreased. Glutathione addition before freezing decreased sperm chromatin immaturity (SCI) percent compared to the control (22.98 ± 0.83, 20.79 ± 0.56). The post-thaw performance of the swim-up technique resulted in a select sperm population with high progressive motility (p = 0.04) and an improvement in DNA integrity in the treated group versus the control group after thawing.

CONCLUSION

The DNA integrity in normozoospermic samples was improved by adding 5 mM glutathione before freezing. Performing the swim-up technique after thawing had no effect on sperm quality in asthenozoospermic patients.

Sperm Cryopreservation Today: Approaches, Efficiency, and Pitfalls

The cryopreservation of human spermatozoa has been an option for patients undergoing chemo or radiotherapies since the late 1950s. Presently, there are different techniques for the cryopreservation of spermatozoa. The most commonly used techniques are programmable slow freezing and freezing on liquid nitrogen vapors, while the use of vitrification is still not accepted as clinically relevant. Although there have been many improvements, the ideal technique for achieving better post-thaw sperm quality continues to be a mystery. A major obstacle during cryopreservation is the formation of intracellular ice crystals. Cryodamage generated by cryopreservation causes structural and molecular alterations in spermatozoa. Injuries can happen because of oxidative stress, temperature stress, and osmotic stress, which then result in changes in the plasma membrane fluidity, motility, viability, and DNA integrity of the spermatozoa. To prevent cryodamage as much as possible, cryoprotectants are added, and in some clinical trial cases, even antioxidants that may improve post-thaw sperm quality are added. This review discusses cryopreservation techniques, cryodamage on molecular and structural levels, and cryoprotectants. It provides a comparison of cryopreservation techniques and describes recent advances in those techniques.

Human Sperm as an In Vitro Model to Assess the Efficacy of Antioxidant Supplements during Sperm Handling: A Narrative Review

Spermatozoa are highly differentiated cells that produce reactive oxygen species (ROS) due to aerobic metabolism. Below a certain threshold, ROS are important in signal transduction pathways and cellular physiological processes, whereas ROS overproduction damages spermatozoa. Sperm manipulation and preparation protocols during assisted reproductive procedures-for example, cryopreservation-can result in excessive ROS production, exposing these cells to oxidative damage. Thus, antioxidants are a relevant topic in sperm quality. This narrative review focuses on human spermatozoa as an in vitro model to study which antioxidants can be used to supplement media. The review comprises a brief presentation of the human sperm structure, a general overview of the main items of reduction-oxidation homeostasis and the ambivalent relationship between spermatozoa and ROS. The main body of the paper deals with studies in which human sperm have been used as an in vitro model to test antioxidant compounds, including natural extracts. The presence and the synergic effects of different antioxidant molecules could potentially lead to more effective products in vitro and, in the future, in vivo.

Ceratonia siliqua L improved cryodamage of asthenozoospermic specimens: An experimental study

Background

Sperm freezing is an important procedure in assisted reproductive technology. Freezing results in physical and chemical changes in the sperm. Ceratonia siliqua L (C.siliqua) is a tree that has antioxidant properties.

Objective

This study aimed to investigate the effect of different concentrations of C.siliqua in a freezing medium on semen parameters, and some biochemical parameters in asthenozoospermic specimens.

Materials and Methods

Forty asthenozoospermic specimens (semen specimens with motility < 32%) were obtained from men aged between 20-40 yr according to the World Health Organization criteria. Each sample was divided into 6 groups: I) fresh, II) control, III) 5, IV) 10, V) 20, and VI) 30 µg/ml C.siliqua extract were added to a freezing medium respectively. Then sperm parameters, malondialdehyde, total antioxidant capacity, reactive oxygen species, and sperm DNA assay were evaluated using related protocols after thawing.

Results

Data analysis shows that sperm parameter, and total antioxidant capacity level increased at a concentration of 20 µg/ml of C.siliqua extract compared to the other concentrations of C.siliqua extract after cryopreservation and thawing (p < 0.001). Also, the sperm DNA fragmentation assay, reactive oxygen species, and malondialdehyde levels were significantly reduced by adding 20 µg/ml of C.siliqua extract to the sperm freezing medium compared to the other treated groups after cryopreservation (p < 0.001).

Conclusion

C.siliqua extract significantly improved sperm parameters after cryopreservation and thawing in asthenozoospermic specimens, and the greatest impact was observed at the 20 µg/ml C.siliqua L extract concentration (p < 0.001).

Curcumin Attenuates Damage to Rooster Spermatozoa Exposed to Selected Uropathogens

Artificial insemination, as an essential pillar of the modern poultry industry, primarily depends on the quality of semen collected from stud roosters. Since the collection and storage of ejaculates is not a sterile process, antimicrobial agents have become essential supplements to semen extenders. While the use of traditional antibiotics has been challenged because of rising bacterial resistance, natural biomolecules represent an appealing alternative because of their antibacterial and antioxidant properties. As such, this study strived to compare the effects of 50 μmol/L curcumin (CUR) with 31.2 µg/mL kanamycin (KAN) as a conventional antibiotic on rooster sperm quality in the presence of Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa. Changes in sperm structural integrity and functional activity were monitored at 2 and 24 h of culture. Computer-assisted semen analysis revealed significant sperm motility preservation following treatment with KAN, particularly in the case of Salmonella enterica and Pseudomonas aeruginosa (p < 0.001) after 24 h. On the other hand, CUR was more effective in opposing ROS overproduction by all bacteria (p < 0.05), as determined by luminol-based luminometry, and maintained sperm mitochondrial activity (p < 0.001 in the case of Salmonella enterica; p < 0.05 with respect to Escherichia coli and Pseudomonas aeruginosa), as assessed by the fluorometric JC-1 assay. The TUNEL assay revealed that CUR readily preserved the DNA integrity of rooster sperm exposed to Salmonella enterica (p < 0.01) and Escherichia coli (p < 0.001). The bacteriological analysis showed higher efficiency of KAN in preventing the growth of all selected bacterial species (p < 0.0001) as opposed to CUR. In conclusion, CUR provided protection to rooster spermatozoa against alterations caused by uropathogens, most likely through its antioxidant activity. Hence, CUR supplementation to poultry semen extenders in combination with properly selected antibacterial substances may become an interesting strategy in the management of bacterial contamination during semen storage.

Effects of water-soluble curcuminoid-rich extract in a solid dispersion form (CRE-SD) on the sperm characteristics, longevity and casein kinase II catalytic subunit alpha protein stability in chilled goat semen

The present study evaluated the effects of water-soluble curcuminoid-rich extract in a solid dispersion form (CRE-SD) on goat sperm qualities and sperm protein CSNK2A2 expression during liquid storage. Semen was collected from five fertile goats, using an artificial vagina. Ejaculates with a motility above 70% were cooled to 4 °C using TRIS-citric acid-fructose diluent with 10% egg yolk containing various concentrations of CRE-SD (0, 0.1, 1, 10 and 100 μg/mL). Chilled sperm were evaluated for sperm characteristics, casein kinase II catalytic subunit alpha (CSNK2A2) protein level and oxidative status up to 15 days. After 12 days of preservation, sperm motility, viability, acrosomal integrity and mitochondrial activity were significantly higher in the group preserved with 10 μg/mL CRE-SD as compared with the control group. Supplementation of CRE-SD at this concentration was also able to conserve the CSNK2A2 a significantly higher than that in control group until 9 days of cold storage, possibly by reducing oxidative stress. The molecular mass of the sperm CSNK2A2 protein detected in this study was 37 kDa; it was mostly located in the post-acrosomal region, midpiece and flagellum. These results demonstrate the possibility to use the CRE-SD as a natural antioxidant during liquid semen storage in goats.

Protective effect of rosiglitazone on microscopic and oxidative stress parameters of ram sperm after freeze-thawing

The purpose of this study was to investigate the effects of rosiglitazone on ram semen after cryopreservation on the quality of thawed sperm. Sperm motility, membrane functionality, viability, total abnormality, acrosome membrane integrity, mitochondrial activity, reactive oxygen species production, ATP content and apoptotic features were assessed after thawing. Rosiglitazone at concentration of 60 µM resulted in the highest (P < 0.05) total motility, progressive motility and straight-line velocity. The percentages of average path velocity and curvilinear velocity were greater in the 60 µM group. Different concentrations of rosiglitazone did not have significant effects on amplitude of the lateral head displacement, linearity and straightness. The highest amounts of membrane functionality and mitochondrial activity after freeze-thawing were observed in groups containing 60 µM. By increasing the rosiglitazone level to 80 µM, no positive effect was observed in most of the evaluated parameters. The lowest ROS concentration was recorded in 60 µM rosiglitazone group (P < 0.05). The group containing 60 µM rosiglitazone also produced the lowest significant percentage of apoptosis-like changes and dead sperm. A greater (P < 0.05) percentage of acrosome integrity in frozen-thawed spermatozoa was observed in the 60 µM rosiglitazone group. There was no significant difference between 40 and 60 µM rosiglitazone in intact acrosome of ram thawed semen. The result showed that supplementation in ram semen extender with rosiglitazone had a positive role in the regulation of ram sperm motility and had strong protective effect on the sperm membrane and acrosome integrity.

The effect of curcumin on NRF2/Keap1 signalling pathway in the epididymis of mouse experimental cryptorchidism

Nrf2/Keap1 pathway, which prevents cellular damage against reactive oxygen species production, is disrupted in epididymis following cryptorchidism. In this study, we aimed to use curcumin (Cur) as an activator of Nrf2 to decrease the effects of disruption in this pathway caused by cryptorchidism. In this study, animals were randomly divided into following groups: control, sham-surgery, sham-vehicle, sham-Cur_50, sham-Cur₁₀₀ , cryptorchidism, cryptorchidism-vehicle, cryptorchidism-Cur₅₀ and cryptorchidism-Cur₁₀₀ . For cryptorchidism induction, the left testicle was removed from the scrotum and sutured to the abdominal wall. Two weeks after surgery, Cur was given orally to animals. After 1 month, sperm parameters and testis histopathology were analysed. The expression of Nrf2, NQO1, HO1, and Keap1 genes was evaluated by real-time polymerase chain reaction. Our data showed that Cur, especially at high doses, could improve sperm parameters and testis histopathology, which were damaged following cryptorchidism induction. The expression of HO1, NQO1, and Nrf2 genes, which had decreased in the cryptorchidism group, showed a significant increase after administration of Cur in a dose-dependent manner. Cur, by inducing the expression of genes involved in the Nrf2/Keap1 pathway, could reduce the adverse effects of cryptorchidism and might be used as adjuvant therapy for decreasing cryptorchidism complications before surgery.

Impact of Escherichia coli Outer Membrane Vesicles on Sperm Function

Reproductive tract infections account for approximately 15% of male infertility cases. Escherichia coli (E. coli) represents the most frequently isolated bacterial strain in the semen of infertile men. All Gram-negative bacteria constitutively produce outer membrane vesicles (OMVs). The present study proved, for the first time, the involvement of OMVs in human sperm function. E. coli OMVs were isolated by ultracentrifugation and characterized via sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Human sperm was exposed to OMVs (8 µg/mL) for different times (30, 45, 60 and 90 min). The vitality, motility, morphology, ROS level and DNA fragmentation of spermatozoa were evaluated. OMVs reduced the progressive motility and increased the immobile spermatozoa amount after 30 min of treatment. In addition, a significant increase in the percentage of intracellular ROS and sperm DNA fragmentation was recorded for each vesicular exposure time. These preliminary findings prove that OMVs contribute to altering human sperm function via two mechanisms: (i) impaired motility and (ii) DNA fragmentation.

L-proline as a novel additive to cryopreservation media improved post-thaw quality of human spermatozoon via reducing oxidative stress

Sperm cryopreservation as a routine technique in assisted reproductive technique (ART) laboratories has detrimental effects on spermatozoa. Various methods have been introduced to improve it. The aim of this research was to evaluate the effects of L-proline supplementation in cryopreservation medium on normozoospermic semen samples. A total of 30 semen samples were collected from normozoospermic men. Cryopreservation media were supplemented with different concentrations of L-proline (0, 1, 2 and 4 mmol/L). The semen samples were cryopreserved. After thawing, sperm parameters and chromatin integrity (aniline blue (AB), toluidine blue (TB), sperm chromatin dispersion test (SCD) and chromomycin A3 (CMA3)), reactive oxygen species (ROS), and total antioxidant capacity (TAC) and malondialdehyde (MDA) levels were evaluated. A total of 4 mmol/L L-proline significantly improved progressive motility and viability (p < 0.05). MDA and ROS levels significantly diminished in samples were cryopreserved by 4 mmol/L L-proline supplemented cryopreservation media (p < 0.001). Also, it significantly increased TAC level. Also, chromatin damages (AB, TB and CMA3) significantly improved in samples were cryopreserved by 4 mmol/L L-proline supplemented cryopreservation media (p < 0.05). The results support that the usage of L-proline supplemented cryopreservation media to improve sperm quality after cryopreservation.

Beneficial effects of hypotaurine supplementation in preparation and freezing media on human sperm cryo-capacitation and DNA quality

BACKGROUND

Although widely used, slow freezing considerably modifies the functions of human spermatozoa. Cryopreservation induces nuclear sperm alterations and cryo-capacitation, reducing the chances of pregnancy. Hypotaurine is naturally present in the male and female genital tracts and has capacitating, osmolytic and anti-oxidant properties. The analysis were performed on surplus semen of men with normal (n = 19) or abnormal (n = 14) sperm parameters. Spermatozoa were selected by density gradient centrifugation before slow freezing. For each sample, these steps were performed in parallel with ("H+" arm) or without ("H-" arm) hypotaurine supplementation. After thawing, we measured total and progressive mobility, vitality, acrosome integrity, markers of capacitation signaling pathway and nuclear quality. For the latter, we focused on sperm chromatin packaging, DNA fragmentation and the presence of vacuoles in the sperm nucleus.

RESULTS

Post-thaw spermatozoa selected and frozen in the presence of hypotaurine had a higher vitality (+ 16.7%, p < 0.001), progressive and total motility (+ 39.9% and +  21.6% respectively, p < 0.005) than spermatozoa from the control "H-" arm. Hypotaurine also reduced the non-specific phosphorylation of the capacitation protein markers P110 and P80 (p < 0.01), indicating a decrease in cryo-capacitation. Hypotaurine supplementation reduced chromatin decondensation, measured by chromomycin A3 (- 16.1%, p < 0.05), DNA fragmentation (- 18.7%, p < 0.05) and nuclear vacuolization (- 20.8%, p < 0.05).

CONCLUSION

Our study is the first to demonstrate beneficial effects of hypotaurine supplementation in preparation and freezing procedures on human spermatozoa sperm fertilization capacity and nucleus quality. Hypotaurine supplementation limited cryo-capacitation, increased the proportion of live and progressively motile spermatozoa and reduces the percentage of spermatozoa showing chromatin decondensation, DNA fragmentation and nuclear vacuolation.

TRIAL REGISTRATION

Clinical Trial, NCT04011813 . Registered 19 May 2019 - Retrospectively registered.

Effect of curcumin on sperm parameters after the cryopreservation

OBJECTIVE

Cryopreservation refers to the cooling of cells and tissues to sub-zero temperatures in order to stop all biologic activity and preserve them for future use. Human sperm cryopreservation is an important tool for assisted reproductive technology and male fertility preservation. However, cryopreservation significantly reduces the quality of spermatozoa. The antioxidant effects of curcumin on different cells have been widely reported. This study was aimed to evaluate changes in post-thaw viability, morphology, motility, chromatin condensation and DNA integrity in response to the addition of curcumin to human sperm freezing extender.

MATERIALS AND METHODS

Semen of 23 normozoospermic men was collected and each sample was divided into three equal aliquots: Control, DMSO, Curcumin. The samples were analyzed freshly for viability (Eosin Y), morphology (Diff-Quick), motility (following WHO standarts), sperm chromatin packaging (aniline blue) and DNA integrity (acridine orange). The control group remained untreated and was mixed with cryopreservation medium (in-house 1:1). The DMSO group was mixed with cryopreservation medium containing 0.1% DMSO. The curcumin group was mixed with cryopreservation medium containing 10 µM curcumin. Samples stained with Diff-Quick and aniline blue were examined under light microscope, samples stained with Eosin Y were examined under phase-contrast microscope and samples stained with acridine orange were examined under fluorescence microscope. Ten days after cryopreservation, samples were thawed and pre-freeze analyses repeated.

RESULTS

Obtained results showed that cryopreservation significantly (P < 0.001) reduces sperm parameters. In Curcumin group, progressive motility, sperm chromatin condensation and DNA integrity significantly (P < 0.001) increased after the thawing process, as compared with the control and the DMSO group.

CONCLUSION

These results suggest that the addition of curcumin to cryopreservation medium improves post-thaw progressive motility, sperm chromatin condensation and DNA integrity. It seems that curcumin ameliorates detrimental effects of cryopreservation on human spermatozoa. Further research is needed on the use of curcumin and other antioxidant substances in sperm cryopreservation.

Anti-Genotoxicity Evaluation of Ellagic Acid and Curcumin—An In Vitro Study on Zebrafish Blood Cells

Genotoxicity is the ability of specific substances to cause DNA damage, affecting development, physiology, and reproduction. This is often mediated by induction of oxidative stress. This in vitro study aims to test the ability of two antioxidants, ellagic acid (EA, 100 µM) and curcumin (Cur, 40 µM) to protect zebrafish blood cells from the genotoxic action of benzene (10 µL/mL). Cells were treated for 30, 60, and 90 min with EA or Cur alone and in combination with benzene. The antigenotoxic role of antioxidants was evaluated in terms of cytotoxicity by trypan blue dye, genome stability by RAPD-PCR technique, DNA fragmentation and percentage of apoptotic cells using Comet and Diffusion assay, respectively. The results did not show statistical differences in terms of cell viability, genome stability, DNA damage and apoptosis between cells treated with antioxidants. When zebrafish blood cells were co-incubated with individual antioxidants and benzene, a significant improvement of these parameters was observed in comparison with cells incubated in benzene. Our results suggested that EA and Cur are able to protect zebrafish blood cells against DNA damage and apoptosis caused by mutagenic substance, and laid the foundation for future studies investigating their antigenotoxic potential in DNA oxidative damage therapy.

The Role of Selected Natural Biomolecules in Sperm Production and Functionality

Emerging evidence from in vivo as well as in vitro studies indicates that natural biomolecules may play important roles in the prevention or management of a wide array of chronic diseases. Furthermore, the use of natural compounds in the treatment of male sub- or infertility has been proposed as a potential alternative to conventional therapeutic options. As such, we aimed to evaluate the effects of selected natural biomolecules on the sperm production, structural integrity, and functional activity. At the same time, we reviewed their possible beneficial or adverse effects on male reproductive health. Using relevant keywords, a literature search was performed to collect currently available information regarding molecular mechanisms by which selected natural biomolecules exhibit their biological effects in the context of male reproductive dysfunction. Evidence gathered from clinical trials, in vitro experiments and in vivo studies suggest that the selected natural compounds affect key targets related to sperm mitochondrial metabolism and motion behavior, oxidative stress, inflammation, DNA integrity and cell death. The majority of reports emphasize on ameliorative, stimulating and protective effects of natural biomolecules on the sperm function. Nevertheless, possible adverse and toxic behavior of natural compounds has been indicated as well, pointing out to a possible dose-dependent impact of natural biomolecules on the sperm survival and functionality. As such, further research leading to a deeper understanding of the beneficial or adverse roles of natural compounds is necessary before these can be employed for the management of male reproductive dysfunction.

DNA Damage in Human Amniotic Cells: Antigenotoxic Potential of Curcumin and α-Lipoic Acid

Oxidative imbalances in the gestational phase are responsible for certain complications during pregnancy and for foetal and neonatal genetic disorders. In this work, using human amniocytes, we aimed to evaluate the protection provided to foetal DNA by two concentrations of antioxidant molecules, α-lipoic acid (LA) and curcumin (Cur), against hydrogen peroxide (H₂O₂)-induced damage. Genotoxicity tests, performed by the random amplification of polymorphic DNA (RAPD-PCR) technique and TUNEL tests, showed that the lowest concentration of LA-protected cells and DNA from H₂O₂ insults. However, a greater ability to protect the amniocytes’ DNA against H₂O₂ was observed following co-treatment with the highest concentration of Cur with H₂O₂. In fact, a genomic template stability (GTS%) similar to that of the negative control and a statistically significant reduction in the DNA fragmentation index (DFI) were revealed. Moreover, following a combined treatment with both antioxidants and H₂O₂, no statistical difference from controls was observed, in terms of both induced mutations and DNA breaks. Furthermore, no effect on morphology or cell viability was observed. The results demonstrate the ability of LA and Cur to protect the genetic material of amniocytes against genotoxic insults, suggesting their beneficial effects in pathologies related to oxidative stress.

Overview on the Antioxidants, Egg Yolk Alternatives, and Mesenchymal Stem Cells and Derivatives Used in Canine Sperm Cryopreservation

Sperm cryopreservation is a widely used assisted reproductive technology for canine species. The long-term storage of dog sperm is effective for the breeding of dogs living far apart, scheduling the time of artificial insemination that suits the female, and preventing diseases of the reproductive tract. However, spermatozoa functions are impaired during the freeze-thaw processes, which may decrease reproductive performance. Numerous attempts have been made to restore such impairments, including the use of cryoprotectants to prevent the damage caused by ice crystal formation, and supplementation of antioxidants to reduce reactive oxygen species generation due to osmotic stress during the procedure. Egg yolk derivatives, antioxidants, and, more recently, mesenchymal stem cells (MSCs) and their derivatives have been proposed in this research field. This review article will summarize the current literature available on the topic.